| 1. Frequency Response (Magnitude) |
- Ripple in both stopband and passband
- Most severe roll-off among all the classical filters
- Sharpest transition band
|
- Ripple only in passband
- Monotonic stopband
- Faster roll-off than Butterworth but slower than Cauer
|
- Ripple only in the stopband
- Flat passband
- Steeper roll-off than Type I, but not sharper than Cauer
|
| 2. Filter Order (Design Complexity) |
- Loses given specifications with smallest possible order
- Most efficient in filter order
- High design complexity due to control of both stopband and passband ripples
|
- Moderate order required for spec
- Higher than Cauer for the same roll-off
- Simpler to design than Cauer
|
- Less stages than Type I for the same stopband attenuation
- More complex than Type I but less complex than Cauer
|
| 3. Ripple Characteristics |
- Ripple in stopband and passband
- Ripple levels are design parameters
- Most "compact" frequency response
|
- Ripple only in the passband
- Stopband is smooth and monotonic
|
- Only ripples in stopband
- Flat passband
|
| 4. Roll-off (Transition Band) |
- Hardest roll-off for any given order
- Optimum selectivity performance
- Most suitable for close specs
|
- Faster than Butterworth, but slower than Cauer
- Good selectivity vs. complexity trade-off
|
- Sharper than Type I
- Not sharper than Cauer
|
| 5. Phase Response & Group Delay |
- Extremely non-linear phase response
- Can introduce serious distortion in phase-critical use
- Often needs phase compensation
|
- Non-linear phase, though usually less so than Cauer
- May be acceptable for non-phase-critical use
|
- Also non-linear phase, perhaps the same or slightly better than Cauer depending on design
|